在OpenCV中利用鼠標繪制矩形和截取圖像的矩形區域

這是兩個相關的程序，前者是後者的基礎。實際上前一個程序也是在前面博文的基礎上做的修改，請參考《在OpenCV中利用鼠標繪制直線》http://www.linuxidc.com/Linux/2012-09/70011.htm 。下面貼出代碼。

程序之一，在OpenCV中利用鼠標繪制矩形

1. #include <cv.h>
2. #include <highgui.h>
3. #include <stdio.h>
4. #pragma comment( lib, "cv.lib" )
5. #pragma comment( lib, "cxcore.lib" )
6. #pragma comment( lib, "highgui.lib" )
7. IplImage* src = 0;
8. IplImage* dst = 0;
9. void on_mouse( int event, int x, int y, int flags, void* ustc)
10. {
11. static CvPoint pre_pt = {-1,-1};
12. static CvPoint cur_pt = {-1,-1};
13. CvFont font;
14. cvInitFont(&font, CV_FONT_HERSHEY_SIMPLEX, 0.5, 0.5, 0, 1, CV_AA);
15. char temp[16];
17. if( event == CV_EVENT_LBUTTONDOWN )
18. {
19. cvCopy(dst,src);
20. sprintf(temp,"(%d,%d)",x,y);
21. pre_pt = cvPoint(x,y);
22. cvPutText(src,temp, pre_pt, &font, cvScalar(0,0, 0, 255));
23. cvCircle( src, pre_pt, 3,cvScalar(255,0,0,0) ,CV_FILLED, CV_AA, 0 );
24. cvShowImage( "src", src );
25. cvCopy(src,dst);
26. }
27. else if( event == CV_EVENT_MOUSEMOVE && !(flags & CV_EVENT_FLAG_LBUTTON))
28. {
29. cvCopy(dst,src);
30. sprintf(temp,"(%d,%d)",x,y);
31. cur_pt = cvPoint(x,y);
32. cvPutText(src,temp, cur_pt, &font, cvScalar(0,0, 0, 255));
33. cvShowImage( "src", src );
34. }
35. else if( event == CV_EVENT_MOUSEMOVE && (flags & CV_EVENT_FLAG_LBUTTON))
36. {
37. cvCopy(dst,src);
38. sprintf(temp,"(%d,%d)",x,y);
39. cur_pt = cvPoint(x,y);
40. cvPutText(src,temp, cur_pt, &font, cvScalar(0,0, 0, 255));
41. cvRectangle(src, pre_pt, cur_pt, cvScalar(0,255,0,0), 1, 8, 0 );
42. cvShowImage( "src", src );
43. }
44. else if( event == CV_EVENT_LBUTTONUP )
45. {
46. sprintf(temp,"(%d,%d)",x,y);
47. cur_pt = cvPoint(x,y);
48. cvPutText(src,temp, cur_pt, &font, cvScalar(0,0, 0, 255));
49. cvCircle( src, cur_pt, 3,cvScalar(255,0,0,0) ,CV_FILLED, CV_AA, 0 );
50. cvRectangle( src, pre_pt, cur_pt, cvScalar(0,255,0,0), 1, 8, 0 );
51. cvShowImage( "src", src );
52. cvCopy(src,dst);
53. }
54. }
55. int main()
56. {
57. src=cvLoadImage("lena.jpg",1);
58. dst=cvCloneImage(src);
59. cvNamedWindow("src",1);
60. cvSetMouseCallback( "src", on_mouse, 0 );
62. cvShowImage("src",src);
63. cvWaitKey(0);
64. cvDestroyAllWindows();
65. cvReleaseImage(&src);
66. cvReleaseImage(&dst);
67. return 0;
68. }

效果圖如下